Last week, the U.S. Fish and Wildlife Service (Service) announced (pdf) that it will begin a status review of the upper Missouri River distinct population segment (DPS) of the Arctic grayling (Thymallus arcticus). The status review will allow the Service to determine whether the DPS should be listed as threatened or endangered under the Endangered Species Act (ESA).

The Arctic grayling is found primarily in the Arctic and Pacific oceans, although some populations are river-dwelling. The fish has a long, thin body with a forked tail and can grow up to 13 inches long. The DPS that is the subject of the Service’s review inhabits watersheds in the upper Missouri River basin upstream of Great Falls, Montana. Threats to the population include dam building and predation.

The species was first placed on the candidate list in 1994. In 2010, the Service determined the upper Missouri River population was considered a DPS under the ESA, and found that listing the DPS was warranted but precluded by higher priority listing actions. The Service’s current status review is the result of its 2011 settlement with WildEarth Guardians, under which the agency must issue decisions on 252 candidate species by 2016.

According to the announcement, the Service will accept information regarding the DPS through December 26, 2013.